Solar photovoltaic systems

Photovoltaic systems (or solar panels), only require daylight, rather than direct sunlight to generate electricity so they work even on a cloudy day.

They directly convert the sun’s light into electricity using solar cells. In simple terms, the light passes through the photovoltaic modules (panels) which produce direct current (DC) electricity. This then passes through an inverter which transforms the DC electricity into the alternating current (AC) electricity commonly used.

High current levels can be experienced with DC electricity which can pose problems with firefighting, particularly as the solar panels cannot simply be switched off and can continue to operate even when damaged. Delays can occur in making the premises safe for firefighters possibly exacerbating the extent of the loss. Specialist fire extinguishing mediums have been developed for dealing with solar photovoltaic (PV) fires and fire and rescue services are equipped with these extinguishers.

Fire can melt the roof anchors securing PV panels allowing them to cascade down the roof and a burning PV panel can release significant amounts of toxic gas.

Another issue is that the structural strength of the building/roof may not have been fully assessed prior to installation which could result in early roof collapse in the event of fire.

To reduce the risks associated with solar voltaic panels you should:

• Always use MCS (Microgeneration Certification Scheme) certificated installers. This should cover all stages of the operation - design, installation and maintenance.
• Conduct periodic electrical safety checks completed by a qualified electrician in accordance with BS7671. The frequency of inspection/testing should be determined by risk assessment.
• Always investigate the structural suitability of the building/roof. This not only needs to withstand the weight of the panels but also any additional snow or wind loading.
• Always ensure a DC Isolating switch is installed and clearly labelled. Most new installations will include an AC Isolating switch and this also needs to be clearly labelled.
• Review and update Fire and Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) risk assessments for the building to reflect the presence of the panels.
• Ensure you liaise with fire and rescue services on the location of panels and, in particular, isolation switches, when developing emergency plans. The emergency contact sheet should include the contact details of the distribution network and the installers.

Read more about the safe installation and management of solar panels